This is the first article in a series on common usability and graphical user interface related terms. On the internet, and especially in forum discussions like we all have here on OSNews, it is almost certain that in any given discussion, someone will most likely bring up usability and GUI related terms - things like spatial memory, widgets, consistency, Fitts' Law, and more. The aim of this series is to explain these terms, learn something about their origins, and finally rate their importance in the field of usability and (graphical) user interface design. We start off with spatial memory - my personal favourite.